Map VS Vec

map_vs_vec.cpp

#include <map>
#include <vector>
#include <chrono>
#include <iostream>
#include <algorithm>

bool comp( const std::pair<size_t, size_t>& lhs, const std::pair<size_t, size_t>& rhs ) {return lhs.first < rhs.first; }

int _tmain(int argc, _TCHAR* argv[])
{

	const size_t count = 1000000;

	std::map<size_t, size_t> my_map;
	for( size_t i = 0; i < count; ++i )
	{
		my_map.insert( { i, i } );
	}

	auto start = std::chrono::high_resolution_clock::now();
	
	for( size_t i = 0; i < count; ++i )
	{
		auto it = my_map.find( i );
	}
	auto elapsed = std::chrono::high_resolution_clock::now() - start;
	long long microseconds = std::chrono::duration_cast<std::chrono::milliseconds>( elapsed ).count();
	std::cout << microseconds << std::endl;

	///////////////////////////////////////////////////////////////////////////

	std::vector<std::pair<size_t, size_t>> my_vec;
	for( size_t i = 0; i < count; ++i )
	{
		my_vec.emplace_back( i, i );
	}

	start = std::chrono::high_resolution_clock::now();

	for( size_t i = 0; i < count; ++i )
	{
		auto it = std::lower_bound( my_vec.cbegin(), my_vec.cend(), std::pair<size_t, size_t>{ i, i }, comp);
	}

	elapsed = std::chrono::high_resolution_clock::now() - start;
	microseconds = std::chrono::duration_cast<std::chrono::milliseconds>( elapsed ).count();
	std::cout << microseconds << std::endl;

	return 0;
}